package com.ambow.core.util;

import java.util.Random;

public class CommonUtil {
	
	public static String genRandomNum(int pwd_len){
		  //35是因为数组是从0开始的，26个字母+10个数字
		  final int  maxNum = 36;
		  int i;  //生成的随机数
		  int count = 0; //生成的密码的长度
		  char[] str = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
		  
		  StringBuffer pwd = new StringBuffer("");
		  Random r = new Random();
		  while(count < pwd_len){
		   //生成随机数，取绝对值，防止生成负数，
		   
		   i = Math.abs(r.nextInt(maxNum));  //生成的数最大为36-1
		   
		   if (i >= 0 && i < str.length) {
		    pwd.append(str[i]);
		    count ++;
		   }}
		   return pwd.toString();
	}
}
